Unit for dry cleaning textile articles using a composite solvent and for recycling the used composite solvent for re-use

ABSTRACT

The invention relates to a unit for dry cleaning textile articles using a composite solvent comprising multiple components, said unit including: a dry cleaning chamber ( 1 ) configured to mix the textile articles to be cleaned with the composite solvent during a cleaning cycle; a device ( 7 ) for recovering the used composite solvent after a cleaning cycle; a treatment device ( 8 ) for removing water and dirt and recycling at least part of the used composite solvent in order to use same in another dry cleaning cycle. The unit is characterised in that it also comprises a re-adjustment device ( 9 ) for re-adjusting the composition of the recycled composite solvent, incorporating therein at least the part of the component(s) that was lost in the treatment device ( 8 ), said re-adjustment device comprising at least: a buffer tank ( 10 ) provided with at least one supply inlet ( 10   a ) for the recycled composite solvent, at least one supply inlet ( 10   b ) for at least the part of the component(s) of the composite solvent to be introduced into the buffer tank ( 10 ) in order to re-adjust the composition of the recycled composite solvent, and at least one outlet ( 10   c ) for the re-adjusted and recycled composite solvent, said outlet ( 10   c ) being connected to the storage tank ( 5 ) for the dry cleaning composite solvent; a storage tank ( 11 ) for one or more components of the dry cleaning composite solvent; and a metering pump ( 14 ) for metering the quantity of the component(s) of the composite solvent to be introduced into the buffer tank ( 10 ) through the inlet ( 10   b ) in order to re-adjust the composition of the recycled composite solvent, said pump being linked upstream to at least one storage tank ( 11 ) containing one or more components of the dry cleaning composite solvent.

TECHNICAL FIELD OF THE INVENTION

The invention has for object a unit for dry cleaning textile articlesusing a composite solvent comprising multiple components and forrecycling used composite solvent for the purposes of re-using it.

The technical field of the invention can, in general, be defined as thatof techniques for dry cleaning clothing, textiles, fabrics and similaritems, and more particularly techniques for recycling dirty solvents inorder to re-use them.

STATE OF THE ART

The methods for dry cleaning textile articles use, in the washing phase,an organic solvent. The latter can be a single-component solvent such asperchloroethylene which is classified as a possible carcinogen (category3) by the European Union and which is now banned in France, or acomposite solvent comprising multiple components such as aqueoussolutions of propylene glycol ethers (see for example the documents ofU.S. Pat. No. 6,273,919 (Hayday, W. A.), U.S. Pat. No. 7,144,850 (Galicket al.)); mixtures of C₁₀-C₁₃ aliphatic hydrocarbons such as the solventEcosolv® marketed by Chevron Phillips®; compositions comprising avolatile siloxane and an organic surfactant, and optionally water (seeU.S. Pat. No. 6,521,580 (Perry et al.)); or compositions comprising asiloxane solvent and/or a hydrocarbon solvents and an amplifyingcompound with a KB value of the composition (US2012/0085634 (Douglas etal.).

Typically, a method for dry cleaning textile articles comprises thesteps consisting in: (a) placing the textile articles to be cleaned incontact with the liquid solvent in a washing and drying machine providedwith a cleaning and stirring basket in rotation about a horizontal axis;(b) subjecting the textile articles in the presence of the solvent torotation movements (alternating-reversed) in order to ensure removal ofthe dirt contaminating the textile articles; (c) extracting the usedsolvent from the basket by pumping, (d) subjecting the cleaned textilearticles to centrifugation in order to extract the greatest possibleamount of used solvent, and (e) removing the residual solvent byvaporization by injecting a flow of hot air through the textilearticles.

After a dry cleaning cycle, the recovered solvent, is most oftencontaminated by different sorts of dirt, namely (i) insoluble dirt suchas dust, balls or isolated strands of textile fibers and dyeing pigmentsdetached from cleaned articles and (ii) soluble dirt such as fat, fattyacids coming from transpiration, coloring agents, etc. The recoveredsolvent is also very often contaminated by the water that comes from therelative humidity of the air, moisture (ex. sweat) contained in thetextile articles to be cleaned, and/or the water introduced into thecleaning device following operations of pre-treating textile articlesfor example with aqueous stain-removing or aqueous pre-brushingsolutions.

However, for reasons concerning public health and protecting theenvironment, but also the cost of the solvent, it is not desirable todiscard the used solvent. It is as such common to recycle, in particularby distillation, the used solvent in the same dry cleaning machine forthe purpose of re-using it in one or several new dry cleaning cycles.

Document US2012/0085634 (Douglas et al.) discloses a method for drycleaning textile articles using a composition constituted of a drycleaning agent comprising a siloxane solvent, a hydrocarbon solvent ormixtures thereof and an amplifying compound, which makes it possible toincrease a KB value of said composition. This method also comprises therecycling via distillation of the used cleaning composition for thepurpose of re-using it. However, this method requires the implementingof a first energy-consuming atmospheric distillation (at more than 100°C.) but above all time-consuming, during which the water, azeotropes,and other volatile compounds are removed, followed by a seconddistillation under reduced pressure (at around 150° C.) during which thedry cleaning agent and the amplifying compound are recovered andredirected to the storage tank in order to be re-used. This method isdelicate to implement for the recycling for the re-use of compositesolvents of which the components can be broken down or be hydrolyzed atsuch temperatures or form separate azeotropes between them and/or withthe water, making the distillation complicated and difficult to managein the dry cleaning machine.

As such, in light of the above, this invention has for purpose topropose a method and a unit for dry cleaning textile articles using acomposite solvent comprising multiple components, which also makes itpossible to satisfactorily regenerate the used solvent for the purposeof a second use.

This invention also has for purpose to propose such a method and such aunit that are simple and safe and which can adapt to different compositesolvents.

DISCLOSURE OF THE INVENTION

The solution proposed by the invention is a unit for the dry cleaning oftextile articles using a composite solvent comprising severalcomponents, said unit comprising:

-   -   a dry cleaning chamber configured to mix, during a cleaning        cycle, the textile articles to be cleaned with the composite        solvent,    -   a device for recovering the used composite solvent after a        cleaning cycle,    -   a treatment device for removing water and dirt and recycling at        least a portion of the used composite solvent for the purpose of        using it for another dry cleaning cycle.

This unit is remarkable by the fact that it further comprises are-adjustment device for re-adjusting the composition of the recycledcomposite solvent by incorporating therein at least the portion of thecomponent or components that was lost in the treatment device, saidre-adjustment device comprises at least:

-   -   a buffer tank provided with at least one supply inlet for the        recycled composite solvent, with at least one supply inlet of at        least the portion of the component or components of the        composite solvent to be introduced into said buffer tank in        order to re-adjust the composition of the recycled composite        solvent, and with at least one outlet of the recycled and        re-adjusted composite solvent, with this outlet being connected        to the storage tank for the dry cleaning composite solvent,    -   a storage tank of one or several components of the dry cleaning        composite solvent, and    -   a metering pump of the quantity of the component or components        of the composite solvent to be introduced into the buffer tank        through said inlet for the re-adjustment of the composition of        the recycled composite solvent, this pump is connected upstream        to at least one storage tank containing one or several        components of the dry cleaning composite solvent.

The advantages of this invention consist in that the unit can be appliedto the dry cleaning composite solvents currently available in themarket, in particular to composite solvents of which the components canform between them and/or with water separate azeotropes and as such makethe regenerating by distillation of the used composite solventcomplicated and difficult to manage in the dry cleaning machine. Theunit of the invention also has the advantage of allowing for the re-useof the recycled composite solvent and in optimum conditions. Indeed,thanks to the step of re-adjusting, the recycled composite solventrecovers at least the portion of the component or components or at leastthe component or components that were lost during the step of treatment,and/or of recycling, with the step of treatment able to be carried outfor example by filtration followed by a conventional distillation,preferably in a vacuum, then by settling; or by fractionateddistillation, preferably in a vacuum.

Other preferred characteristics of the invention are listed hereinbelow,with each one of these characteristics able to be consideredindividually or in combination with the remarkable characteristicsdefined hereinabove:

Preferentially, the re-adjustment device is provided with an analyzermaking it possible to analyze the composition of the recycled compositesolvent, in such a way as to determine the quantity of the component orcomponents of the composite solvent to be taken from the storage tank ortanks of one or several components of the dry cleaning compositesolvent, and to be introduced into the “buffer” tank.

In particular, the cleaning chamber is provided with a perforated drumintended to receive the textile articles to be cleaned, said perforateddrum being mounted rotatingly in said chamber, with the latter having:

-   -   an opening for the placing of textile articles to be dry cleaned        in the perforated drum, with this opening able to be closed by a        door or a porthole,    -   an orifice connected to a duct for introducing the composite        solvent which is placed in a storage tank.    -   an orifice connected to the recovery device.

According to an embodiment, the treatment device for the used compositesolvent comprises at least one filtration device for filtering insolubledirt contained in said used composite solvent and a fractionateddistillation unit, said treatment device comprising:

-   -   an outlet for the removal of an overhead fraction F1        representing less than 15% w/w_(used composite solvent) and        containing at least water, one or several azeotropes formed        between the water and one or several components of the composite        solvent, and    -   an outlet for the recycling of an intermediate fraction F2        representing more than w/w_(used composite solvent) and        containing the dry cleaning composite solvent less at least one        portion, by weight, of one or of several of its components, said        intermediate fraction F2 being placed after recycling in a        buffer tank.

According to another advantageous detail, the fractionated distillationunit is provided with a collection container configured to receive in afirst step the overhead fraction F1 before it is discharged to theremoval tank, then in a second step, the intermediate fraction F2 beforeit is sent to the buffer tank, said collection container:

-   -   having a drawing-off point in its lower portion, through which        the overhead fraction F1 and the intermediate fraction F2 are        removed to their respective tanks; and    -   being provided with an analyzer making it possible to analyze        the physical and/or chemical characteristics of the overhead        fraction F1 or of the intermediate fraction F2 in such a way as        to determine the quantity of the component or components of the        composite solvent to be introduced into said buffer tank.    -   Advantageously, the removal tank intended to contain the        overhead fraction F1, comprises a duct connected to an injection        device making it possible to inject, after N dry cleaning        cycles, said fraction F1 into the fractionated distillation unit        for the purpose of separating it into at least two fractions:        one overhead fraction F′1 intended to be removed, and a fraction        F′2 intended to be added, before the re-adjusting of the        recycled composite solvent, to the intermediate fraction F2        collected after the cycle N of dry cleaning.

Particularly advantageously, the dry cleaning composite solventimplemented in the unit according to the invention, comprises at least:

-   -   40% to 80% w/w_(composite solvent) of dipropylene glycol        monomethyl ether,    -   5% to 40% w/w_(composite solvent) of an amphiphilic solvent A        having the following formula: R—(O—C₃H₆)_(n)—OH (I) wherein n is        an integer equal to 1 or 2, and R an alkyl group in C₃ or in C₄,    -   10% to 40% w/w_(composite solvent) Of a dibasic ester B selected        from the group comprising dimethyl succinate, dimethyl        glutarate, dimethyl adipate and mixtures thereof, and −0% to 10%        w/w_(composite solvent) of additional components.

DESCRIPTION OF THE FIGURES

Other advantages and characteristics of the invention shall appearbetter when reading the following description of a preferred embodiment,in reference to the annexed drawings, provided by way of example for thepurposes of information and not restricted and wherein:

FIG. 1 diagrammatically shows a unit in accordance with the invention.

FIG. 2 diagrammatically shows an alternative according to the invention.

EMBODIMENTS OF THE INVENTION

This invention is based on the experimental findings that the usedcomposite solvents recovered after a first dry cleaning cycle of textilearticles, recycled, in particular via distillation, and used again inanother cleaning cycle, are less effective in removing hydrophilic dirtand/or hydrophobic dirt than starting composite solvents. This drop inperformance can be explained by the fact that during the recyclingoperations, in particular via distillation, composite solvents lose oneor several of their components or a portion of one or more of theircomponents. Such a loss of component(s) or portion of component(s)induces a modification in the composition of the recycled compositesolvents, and therefore a significant modification in the dry cleaningproperties. The applicant resolved this problem of a decrease inperformance experienced by the recycled composite solvents, byincorporating into the composition of the latter at least the portion ofthe component or components that was lost during the recyclingoperations.

In this text:

-   -   “composite solvent” means solvent containing at least two        components playing an essential role in conferring properties of        dry cleaning of textile articles.    -   “dry cleaning” means the cleaning wherein the composite solvents        double as a solvent or cleaning liquid as a replacement for        water.    -   “textile articles” means the object used in a personal or        professional framework (e.g. various industries, hospitals,        etc.), and manufactured using natural fibers such as cotton,        wool, flax, silk or others, and/or from synthetic fibers such as        nylon, polyamide, acrylic, polyester, acetate, viscose, or        others. As examples of textile articles can be mentioned shirts,        pants, sweaters, vests, coats, tablecloths, covers, sheets,        napkins, quilts, leather clothing, suede, etc.    -   “dirt” means the dirt, whether hydrophilic or hydrophobic,        soluble in the composite solvent, and the dirt that is insoluble        therein such as dust, balls or isolated strands of textile        fibers and dyeing pigments detached from cleaned articles or        others.    -   “hydrophobic dirt” means the dirt contaminating the textile        articles and which is generally comprised of organic matter or        materials that do not have an affinity for water and which are        insoluble therein. By way of non-restricted examples of        “hydrophobic dirt” fat, oil, mayonnaise, mustard, body oils, tar        or motor oil stains etc. can be mentioned.    -   “hydrophilic dirt” means the dirt contaminating the textile        articles and which is mainly comprised of organic or inorganic        matter that have certain affinities with water and which are        entirely or partially soluble therein. By way of non-restricted        examples of “hydrophilic dirt”, body fluids such as sweat,        blood, urine, food products that are soluble in water such as        sugar, salt, chocolate, fruit juices, tea, coffee, etc. can be        mentioned.    -   “major portion” according to the invention means the initial        composition of the composite solvent used for the dry cleaning        of textile articles, less at least a portion, by weight, of one        or several components of the composite solvent lost during the        steps of treating and of recycling the used composite solvent.

The percentages, content and ratios used hereinbelow are all given inrelation to the total weight of the composition “w/w_(composite solvent)^(”), unless mentioned otherwise.

Method for Dry Cleaning Textile Articles and for Recycling the UsedComposite Solvent

This invention first aims for a method for dry cleaning textile articlesusing a composite solvent comprising multiple components and recyclingused composite solvent for the purpose of re-use. Advantageously, thismethod comprises:

a) a dry cleaning cycle comprising the putting of the textile articlesto be cleaned in contact with the composite solvent,

b) the recovery of the used composite solvent contaminated by the waterand the dirt after the dry cleaning cycle,

c) the treatment of the used composite solvent in such a way as toremove at least the water and the dirt,

d) the recycling of at least a portion of the composite solvent treatedin the step c) for the purpose of using it for another dry cleaningcycle,

e) the re-adjusting of the composition of the recycled composite solventin the step d) by incorporating into this composition at least theportion of the component or components of the composite solvent that waslost during the steps c) and/or d).

By way of example of composite solvents comprising multiple componentsand suitable for the dry cleaning of textile articles according to thisinvention the composite solvent S can be mentioned that comprise atleast:

-   -   dipropylene glycol monomethyl ether (DPM),    -   an amphiphilic solvent A having the following formula:        R—(O—C₃H₆)_(n)—OH (1) wherein n is an integer equal to 1 or 2,        and R an alkyl group in C₃ or in C₄, and    -   a dibasic ester B selected from the group comprising dimethyl        succinate, dimethyl glutarate, dimethyl adipate and mixtures        thereof.

This composite solvent S was recently developed by the Applicant who wasable to demonstrate that it manifests a strong cleaning power withregards to hydrophobic dirt (fat in particular), but also with regardsto hydrophilic dirt (organic matter or water soluble minerals) which canappear on textile articles. The Applicant also demonstrated that such acomposite solvent can be can be adapted to the type of dirt (hydrophobicor hydrophilic) as well as to the type of textile articles to be drycleaned by varying the proportions of the three essential ingredientsnamely dipropylene glycol monomethyl ether, the amphiphilic solvent Aand the dibasic ester B. The Applicant also noted that this compositesolvent also has the advantage of maintaining, in a solution or in asuspension, the liquid or solid dirt extracted during the operation ofdry cleaning preventing it as such from being re-deposited on thecleaned textile articles.

This composite solvent S can advantageously replace perchloroethylene(PERC) which is classified as a possible carcinogen (category 3) by theEuropean Union and which is now banned in France for its use in drycleaning machines.

The Applicant was further able to demonstrate that the best dry cleaningresults were obtained with composite solvents S comprising: (i)dipropylene glycol monomethyl ether (DPM), mono-n-butyl ether ofdipropylene glycol (PnB) and of dibasic ester DBE; (ii) dipropyleneglycol monomethyl ether (DPM), mono-n-butyl ether of dipropylene glycol(DPnB) and of dibasic ester DBE; or (iii) dipropylene glycol monomethylether (DPM), mono-tert-butyl ether of dipropylene glycol (DPtB) and ofdibasic ester DBE; or (iv) dipropylene glycol monomethyl ether (DPM),mono-n-butyl ether of dipropylene glycol (DPnB), mono-n-propyl ether ofdipropylene glycol (DPnP), and of dibasic ester DBE; or (v) dipropyleneglycol monomethyl ether (DPM), mono-n-butyl ether of dipropylene glycol(DPnB), mono-n-butyl ether of propylene glycol (PnB), and of dibasicester DBE.

Note: The preferred dibasic ester (DBE) according to the invention isthe dibasic ester Rhodiasolv® RPDE marketed by Rhodia.

This composite solvent S (or these composite solvents) canadvantageously further comprise all sorts of additional componentsnormally used in the field of dry cleaning. By way of example,additional components can be chosen from antioxidants, disinfectingagents, perfumes and mixtures thereof. These additional components canbe present in the composition according to this invention in a quantitybetween 0.001% and 10% in w/w_(composition) without substantiallyaffecting its advantageous properties.

By way of example of antioxidant agents (or stabilizers)2,6-di-_(tert)-butyl-p-methylphenol (BHT),2-_(tertio)-butyl-4-hydroxyanisole (2-BHA) and3-tertio-butyl-4-hydroxyanisole (3-BHA) or mixtures thereof can bementioned. Such antioxidant agents have for function to prevent ordecrease or delay a possible formation of peroxides.

By way of examples of disinfecting agents, quaternary ammonium salts,aldehydes, phenolic derivatives, halogenated compounds (e.g. iodinated),alcohols or others can be mentioned. Such disinfecting agents will havethe role of making possible an action of disinfection of the textilearticles to be cleaned, in particular household, medical or veterinarylaundry. They furthermore have a cleaning action of the chamber devotedto dry cleaning.

A preferred composite solvent S for the implementing of the method ofdry cleaning articles according to this invention, comprises:

-   -   40% to 80% w/w_(composite solvent) of dipropylene glycol        monomethyl ether,    -   5% to 40% w/w_(composite solvent) of an amphiphilic solvent A        having the following formula: R—(O—C₃H₆)_(n)—OH (I) wherein n is        an integer equal to 1 or 2, and R an alkyl group in C₃ or in C₄,    -   10% to 40% w/w_(composite solvent) of a dibasic ester B selected        from the group comprising dimethyl succinate, dimethyl        glutarate, dimethyl adipate and mixtures thereof, and −0% to 10%        w/w_(composite solvent) of additional components.

Such a composite solvent S further has the advantage of being able to beprepared by any method of mixing known to those skilled in the art,using non-toxic components, classified as easily biodegradable,inexpensive and available in the market. It advantageously has the formof a limpid and colorless liquid and can be conditioned, in anhydrousstate, in any contained able to receive a liquid, such as for example, astorage tank made of steel or from plastic materials such aspolyethylene and polypropylene.

However, the Applicant was able to note that using such a compositesolvent S in the form of an aqueous solution containing more than 8%w/w_(composite solvent) s of water, does not result in optimum drycleaning.

The step a) of the method according to this invention, can be carriedout by any method of dry cleaning known to those skimmed in the art.Generally, the textile articles are: i) placed in a washing and dryingmachine (known to those skilled in the art) comprising for example aleaktight chamber which is provided with a rotating perforated drum andwhich is connected to a solvent circuit comprising a solvent circulationdevice, ii) placed in contact with the composite solvent, for examplepar immersion, iii) stirred in the composite solvent according to themovement of rotation (alternating-reversed) in order to allow for thedissolution of the dirt contaminating the textile articles, iv) spunthrough centrifugation in order to extract the largest possible quantityof the used composite solvent, and dried v) in order to remove theresidual solvent, for example by injecting a flow of hot air through thetextile articles.

In practice, the phase of stirring iii) can be carried out at atemperature ranging from 15° C. to 60° C. according to the compositesolvent used and the textile articles to be cleaned. This phase ofstirring iii) can be repeated several times, for example two times. Thehot air injected during the drying phase v) has a temperature greaterthan 40° C., preferably between 60° C. to 80° C., according to thecomposite solvent used and the textile articles to be cleaned.

After this dry cleaning cycle, textile articles with the dirt removedand used composite solvent are obtained. In practice, the used compositesolvent is recovered in the step b), on the one hand, by pumping at thestep of spinning iv) and, on the other hand, by cooling the vaporsgenerated during the step of drying v).

The solvent recovered as such is generally contaminated by various sortsof dirt, namely (i) insoluble dirt such as dust, balls or isolatedstrands of textile fibers and the dyeing pigments detached from cleanedarticles and (ii) soluble dirt, whether hydrophilic or hydrophobic, suchas fat, fatty acids coming from transpiration, etc. At this stage, theused composite solvent recovered is also contaminated by the water whichcomes from the relative humidity of the air and/or the moisture (ex.sweat) contained in the textile articles to be cleaned, and/or the waterintroduced into the cleaning device following the operations ofpre-treating textile articles for example with aqueous stain-removing oraqueous pre-brushing solutions.

By way of example, the preferred composite solvent S developed by theApplicant (described hereinabove) is contaminated at this stage by atleast 0.5% w/w_(composite) solvent S of water, in particular by at mostw/w_(composite solvent) S of water, as well as by insoluble dirt andsoluble dirt.

The step c) of the method of this invention has for purpose to purifythe used composite solvent recovered in the step b) by removing at leastthe water, the dirt.

In an advantageous embodiment, the removal of the insoluble dirt iscarried out via filtration on means of filtration selected in the groupconstituted by button (or pin) filters, carbon filters and combinationsthereof. This filtration is constant from the beginning to the end ofthe dry cleaning cycle. The used composite solvent filtered as such issubjected to fractionated distillation. This fractionated distillationis, preferably, conducted under reduced pressure, in such a way as toremove an overhead fraction F1, on the one hand, and to collect anintermediate fraction F2, on the other hand.

The overhead fraction F1 represents less than 15%w/w_(used composite solvent) and contains at least water and one orseveral azeotropes formed between the water and one or severalcomponents of the composite solvent. The overhead fraction F1 can alsocontain one or several components or a portion of one or of severalcomponents of the distilling composite solvent at the same time as thewater without necessarily forming azeotropes with the water.

Note: the expression “w/w_(used composite solvent) ^(”) means that thepercentage is calculated in relation to the total weight of the usedsolvent to be treated by fractionated distillation.

The intermediate fraction F2 shows more than 75%w/w_(used composite solvent) and contains more preferably the drycleaning composite solvent less at least one portion, by weight, of oneor of several of its components, said portion was removed, for example,with the overhead fraction F1 and/or was lost in the bottom fraction ofdistillation as explained hereinbelow.

From a safety standpoint, the bottom fraction of the fractionateddistillation is generally not recovered. It is withdrawn from thedistillation unit and transferred to a tank for later treatment. Thisbottom fraction can contain insoluble dirt and/or soluble dirt. It canalso contain another portion, by weight, of one or several components ofthe composite solvent, even one or several components of the compositesolvent of which the boiling point is too high even under reducedpressure, such as antioxidants, disinfectants and surfactants which arepossibly included in the composition of the dry cleaning compositesolvent.

The step of treating c), more preferably, by filtration followed byfractionated distillation, can be carried out during or in parallel tothe dry cleaning cycle mentioned in the step a).

By way of example, in the case of the preferred composite solvent Sdeveloped by the Applicant (see hereinabove), and contaminated by 5%w/w_(used composite solvent) S of water:

-   -   the overhead fraction F1 removed by fractionated distillation in        the step c), distils at a temperature less than 82° C. and under        a pressure of 65 mBars (or at a temperature between 20° C. and        121° C. under 267 mBars) and comprises at least water,        dipropylene glycol monomethyl ether, and where applicable an        amphiphilic solvent A′ having the following formula:        R′—O—C₃H₆—OH (I′) wherein R′ represents an alkyl group in C3 or        in C4. This overhead fraction F1 can further comprise a fraction        <20% w/w_(overhead fraction F)1 in dibasic ester according to        the conditions chosen for the fractionated distillation. It        represents less than 15% w/w_(used composite solvent S).

and,

-   -   the intermediate fraction F2 collected by fractionated        distillation in the step b) distils at a temperature greater        than 83° C., more preferably between 83° C. and 140° C., under a        pressure of 65 mBars. This intermediate fraction F2 represents        more than 75% w/w_(used composite solvent S), more preferably        more than 95% w/w_(used composite solvent S).

By way of example of amphiphilic solvent A′, mono-n-butyl ether ofpropylene glycol, mono-iso-butyl ether of propylene glycol,mono-tert-butyl ether of propylene glycol, mono-n-propyl ether ofpropylene glycol, mono-isopropyl ether of propylene glycol and mixturesthereof can be mentioned.

The intermediate fraction F2 collected in the step c) therefore has acomposition which is different from that of the composite solvent usedfor dry cleaning. In order to be able to use this fraction F2 in anotherdry cleaning cycle of textile articles, its composition has to bere-adjusted.

In practice, the intermediate fraction F2 (or recycled compositesolvent) is transferred from the treatment unit to a reserve tankwherein it composition will be supplemented by incorporating therein atleast the portion, by weight, of the component or components that waslost during the step c).

By way of example, in the case of the preferred composite solvent S, theportion to be incorporated into the composition of the recycledcomposite solvent (here the intermediate fraction F2) in the step d)comprises at least dipropylene glycol monomethyl ether, and whereapplicable one or several amphiphiles A having the following formulaR—(O—C₃H₆)_(n)—OH (I) wherein n is an integer equal to 1 or 2, Rrepresents an alkyl group in C₃ or in C₄. The portion, by weight, to beincorporated into the composition of the recycled composite solvent canfurther comprise one or several dibasic esters B and/one or severaladditional components.

The treatment and re-adjusting cycle represented by the steps c) to e)described hereinabove is entirely automatic and can be implementedduring or in parallel to the dry cleaning phase of textile articles.

In the case of a treatment of the composite solvent by fractionateddistillation, it may be useful to retreat the overhead fraction F1removed during the fractionated distillation in order to, on the onehand, minimize the volume of the solvent discharge, and, on the otherhand, offset a possible lack in selectivity of the fractionateddistillation. To this effect, this invention propose to recover theoverhead fraction F1 after N dry cleaning cycles and to subject it to afractionated distillation. Typically, this second fractionateddistillation is conducted in such a way as to remove an overheadfraction F′1, and to recover a fraction F′2, said fraction F′2 isintended to be added, before the step e) of re-adjusting, to theintermediate fraction F2 collected after the cycle N of dry cleaning.Generally, the overhead fraction F′1 removed during this secondfractionated distillation contains a preponderant quantity of water. Thenumber N of the dry cleaning cycles after said removed overhead fractionF1 must be recovered, can be determined by those skilled in the artaccording to the composition of the composite solvent implemented andthe selectivity of the fractionated distillation. By way of anon-restricted example, in the case of the preferred composite solvent Sof the invention, the overhead fraction F1 recovered is retreated byfractionated distillation every N cycles of dry cleaning, for exampleevery 10 to 50 cycles of dry cleaning, preferentially every 20 to 30cycles of dry cleaning. In this case, the fraction F′1 containing apreponderant quantity (>50% w/w_(fraction F′1)) of water, distils at atemperature less than 100° c. under 200 mBars and the fraction F′2 to beadded to the fraction F2, distils under pressures less than 70 mBars.

Unit for the Dry Cleaning of Textile Articles and for the Regeneratingof the Used Composite Solvent

The annexed FIGS. 1 and 2 schematize, according to two preferredembodiments, the organization of a unit in accordance with theinvention. This unit comprises at least one dry cleaning chamber (1)configured to mix, during a cleaning cycle, the textile articles to becleaned with the composite solvent; a tank (5) for storing the cleancomposite solvent; a device (8) for treating the used composite solventin order to recycle the latter at least partially; and a device (9) forre-adjusting the composition of the recycled composite solvent. By wayof example, the tank (5) can have a capacity of 120 liters in the caseof a cleaning unit provided for 12 to 14 KG of textile articles to becleaned.

A perforated drum (2), made of stainless steel, intended to receive thetextile articles to be cleaned is mounted rotatingly in the cleaningchamber (1). Typically, this drum (2) is made of stainless steel, has acapacity of 200 L to 1500 L and can receive 9 Kg to 70 kg of textilearticles to be dry cleaned. The rotating speed of the drum during acleaning operation can vary for example from 1 revolution/minute toseveral hundred revolutions/minute, preferably from 300 rpm to 600 rpm,preferentially from 400 rpm to 500 rpm.

The cleaning chamber (1), which is furthermore leaktight, has at leastone opening (20) for the placing of textile articles to be cleaned inthe perforated drum (2), with this opening (20) able to be closed(hermetically) by a door or a porthole; an orifice (3) connected to aduct for introducing (4) clean composite solvent which is placed in thestorage tank (5); and an orifice (6) connected to a duct for recovering(7) used composite solvent after a cleaning cycle.

The duct for the introduction (4) is, generally, provided with at leastthe following means (not shown in FIG. 1):

-   -   a supply pump for conveying the composite solvent stored in the        tank (S) to the cleaning chamber (1),    -   means of heating, such as a heat exchanger, in order to increase        the temperature of the composite solvent for the purpose of        carrying out the cleaning of textile articles at a temperature        higher than the ambient temperature, for example at a        temperature between 25° C. and 50° C.,    -   means, such as a fan, for introducing a flow of hot air (heated        to a temperature greater than 40° C., more preferably between        65° C. to 75° C.) in the cleaning chamber (1) with the purpose        of drying the cleaned textile articles.

After a dry cleaning cycle, the used composite solvent is removed by therecovery duct (7). The latter is, generally, provided with at least:

-   -   one drain valve (not shown) controlled by a control device,    -   one removal pump (not shown) able, on the one hand, to suck the        used composite solvent, and where applicable the residual,        evaporated and condensed composite solvent, from the chamber        (1), and, on the other hand, to transfer it to the treatment        device (8) for the purpose of being recycled at least partially.

According to a preferred embodiment, the treatment device (8) isprovided with a filtration device (12), such as a button (or pin)filter, an active carbon filter or combinations thereof, in order toclarify the used composite solvent, in particular in order to remove theinsoluble dirt; and with a fractionated distillation unit (13) operatingin such a way as to allow for, on the one hand, the removal of anoverhead fraction F1 representing less than 15%w/w_(used composite solvent) and containing at least the water, one orseveral azeotropes formed between the water and one or severalcomponents of the composite solvent; and, on the other hand, therecycling of an intermediate fraction F2 representing more than 75%w/w_(used composite solvent) and containing the dry cleaning compositesolvent less at least one portion, by weight, of one or of several ofits components, said portion which was lost in the step of treatment c).

The fractionated distillation unit (13) comprises at least the followingmeans (not shown in FIG. 1): a distillation column provided at its basewith a distiller and at its head with a condenser associated with avacuum pump. Said distiller is supplied with used composite solvent, bythe duct (12 a) and has for function to vaporize at least partially theused composite solvent. The operating conditions of said distiller areconventional and are according to the used composite solvent to betreated by fractionated distillation, with the latter able to beimplemented by temperature gradient under a constant pressure, or bypressure and temperature gradient.

By way of example, in the case of the preferred composite solvent S (seehereinabove), the temperature in the distiller can be maintained at avalue less than 250° C., for example at a value ranging from 25° C. to180° C., preferably from 120° C. to 160° C. under a reduced pressure of65 mBars.

The fractionated distillation unit (13) has at least a first outlet forthe removal according to the arrow F1 of the overhead fraction F1 to aremoval tank (or fluid container) (30) for later treatment for thepurpose of re-use, and a second outlet for the recovery according to thearrow F2 of the intermediate fraction F2 which is sent via the duct (7a) to the buffer tank (10) wherein it has to be re-adjusted for thepurpose of being re-used in another dry cleaning cycle. By way ofexample, the capacity of the buffer tank (10) can be 60 liters in thecase of a cleaning unit provided for 12 to 14 KG of textile articles.

According to a preferred alternative of the invention, the removal tank(30) containing the overhead fraction F1, comprises a duct (300)connected to an injection device (301) which makes it possible toinject, after N dry cleaning cycles, the fraction F1 into thefractionated distillation unit (13) for the purpose of separating itinto at least two fractions: an overhead fraction F′1 intended to beremoved, and a fraction F′2 intended to be added, before the step ofre-adjusting e) of the recycled composite solvent, to the intermediatefraction F2 collected after the cycle N of dry cleaning.

More precisely, the re-adjustment device (9) of the composition of therecycled composite solvent is comprised of at least:

-   -   the buffer tank (10) provided with at least one supply inlet (10        a) for the recycled composite solvent (intermediate fraction        F2), with at least one inlet (10 b) for the supply with at least        the portion, by weight, of the component or components of the        composite solvent to be introduced into the buffer tank (10) in        order to re-adjust the composition of the recycled composite        solvent (or intermediate fraction F2), and with at least one        outlet (10 c) of the recycled and re-adjusted composite solvent,        with this outlet (10 c) being connected to the storage tank (5)        for the dry cleaning composite solvent,    -   a metering pump (14) of the quantity (predetermined) of the        component or components of the composite solvent to be        introduced into the buffer tank (10) through said inlet (10 b),        this pump is connected upstream to at least one storage tank        (11) of one or several components of the composite solvent. By        way of example, the tank (11) can be of a capacity of 20 liters        in the case of a cleaning unit provided for 12 to 14 KG of        textile articles to be cleaned.

The re-adjustment device (9) can be provided with an analyzer (15)provided on the buffer tank (10) and which makes it possible to analyzethe physical and/or chemical characteristics of the recycled compositesolvent, in such a way as to determine the quantity of the component orcomponents of the composite solvent to be introduced into this buffertank (10). The analyzer (15) consists, for example, of a weightdetector; a liquid level detector; a UV, visible or Infra-Red (IR)spectrometer; a refractometer; or other, said analyzer (15) beingconnected to a computer server of the type that integrates a processorand a memory wherein one or several computer programs are recorded. Thelatter integrate instructions that, when they are executed by theprocessor, make it possible to implement the functionalities definedhereinafter. The analyzer (15) analyzes the physical and/or chemicalcharacteristics of the recycled composite solvent and transfers thisdata to the server. The latter compares the characteristics determinedfor the recycled composite solvent contained in the buffer tank (10)with those of the clean dry cleaning composite solvent. It is thenpossible to determine the quantity of the component or components to betaken in the storage tank or tanks (11) and to be introduced into thebuffer tank (10). The analyzer (15) as such transmits an adapted controlinstruction to the metering pump (14).

According to another alternative of the invention (FIG. 2), thefractionated distillation unit (13) is provided with a collectioncontainer (31) configured to receive in a first step the overheadfraction F1 before it is removed according to the arrow F1 to theremoval tank (30), then in a second step, the intermediate fraction F2before it is sent according to the arrow F2 to the buffer tank (10). Thecollection container (31) has a drawing-off point (31 a) in its lowerportion, through which the overhead fraction F1 and the intermediatefraction F2 are removed to their respective tanks. According to thisalternative, the collection container (31) is provided with an analyzer(15 a) which makes it possible to analyze the physical and/or chemicalcharacteristics of the overhead fraction F1 of the overhead fraction F1or of the fraction F2 before they are removed from said collectioncontainer (31), in such a way as to determine as described hereinabovethe quantity of the component or components of the composite solvent tobe introduced into this buffer tank (10). The analyzer (15 a) can be ofthe same type as the analyzer (15) described hereinabove. According tothis alternative, the buffer tank (10) can also be provided with theanalyzer (15 a) (option not shown). According to another alternative(not shown) only the buffer tank (10) is provided with the analyzer (15a).

Particularly advantageously, the dry cleaning composite solventcomprises at least:

-   -   40% to 80% w/w_(composite solvent) of dipropylene glycol        monomethyl ether,    -   5% to 40% w/w_(composite solvent) of an amphiphilic solvent A        having the following formula: R—(O—C₃H₆)_(n)—OH (I) wherein n is        an integer equal to 1 or 2, and R an alkyl group in C₃ or in C₄,    -   10% to 40% w/w_(composite solvent) Of a dibasic ester B selected        from the group comprising dimethyl succinate, dimethyl        glutarate, dimethyl adipate and mixtures thereof, and    -   0% to 10% w/w_(composite solvent) of additional components.

The various pumps that are provided in the unit of this invention arefor example pumps of the centrifuge, peristaltic or vortex type. And,the various ducts of the unit are provided with valves of which thearrangement makes it possible to circulate the fluids correctly. Thesevarious pumps as well as the various valves can be controlledindependently of each other in order to provide optimum operation of theunit according to the invention.

The unit of this invention is advantageously a semi-industrial unit(hospitals, hotels . . . ) or for launderette or a unit for householduse.

Note:

-   -   the composite solvents of which example is mentioned in this        description (dipropylene glycol monomethyl ether, amphiphilic        solvent A and amphiphilic solvent A′) can exist in the form of        positional isomers, optical isomers or combinations thereof.    -   The term “and/or” used in certain passages of this description,        includes the meanings and, or, as well as all other possible        combinations of the elements connected with this term.

It is of course obvious that various alternatives and improvements canbe made to the cleaning unit without however leaving the scope of theinvention. As such:

-   -   the treatment device, in particular the distillation unit, can        be arranged to the exterior of the cleaning unit, and where        applicable connected to one or several other cleaning units.    -   the distiller of the distillation unit can be provided with a        drawing-off point in its lower portion in order to recover the        heavy fractions that have not distilled, for the purpose of        later treatment.

EXAMPLES Example 1 Preferred Dry Cleaning Composite Solvents

The preferred composite solvents 1 to 6 of the invention are preparedusing the ingredients indicated in the table hereinbelow via any methodknown to those skilled in the art.

Weight proportion (w/w_(composite solvent)) as % Examples: Ingredients 12 3 4 5 6 dipropylene glycol 64 70 70 58 58 64 monomethyl ether (DPM),mono-n-butyl ether of 9 propylene glycol (PnB) mono-n-butyl ether of 1410 20 12 30 5 dipropylene glycol (DPnB) dibasic ester (DBE) 22 20 10 3012 22

The dibasic ester DBE used in examples 1 to 6 is Rhodiasolv® RPOEmarketed by Rhodia®.

Composite solvents 1 to 6 that are anhydrous (not containing any addedwater), limpid and colorless, which are chemically stable, are obtained.These composite solvents can be stored for more than 1 year, and evenmore than 2 years, at a temperature less than 40° C., in closedcontainers and away from air and light. They add, in particular, thefollowing properties:

-   -   compatibility with respect for the environment, human and animal        health, and safety at work in dry cleaning establishments,    -   flash points: greater than 75° C.,    -   Kauri-Butanol index: greater than 70    -   anhydrous (non-aqueous) and can be diluted in water with a        miscibility greater than 40% v/v in water.

Example 2 Effects of Composite Solvents 1 to 6

The effect of composite solvents 1 to 6 as dry cleaning solvents, wasstudied on a panel of fabrics (10 cm×10 cm) constituted of variousfibers as well as on accessories that are frequently encountered on thetextile articles. A first study covered the observation of deformationof the fabrics and the discoloration and the second on the effectivenessof the cleaning of stains.

To carry out these tests, the fabrics were impregnated (via immersion)and mechanically stirred in composite solvents 1 to 6 pendant 10 minthen dried in a ventilated oven at 70° C.

Results:

1) Deformations, Discoloration and Deteriorations of the Linings:

The tests carried out on various fabrics of the polyester, cotton,viscose, flax, acrylic, wool, acetate, elastane, silk types have shownthat the fabrics are correctly washed, dried easily, do not contain anyodor after drying and retain their measurements even in the case of wool(deformation less than 0.2 mm). The experiment on pieces of textiles hasshown that with these composite solvents the fabric is substantiallyless dry than with perchloroethylene, and procures a good sliding whichseriously facilitates ironing, and reduces the risk of felting inmachines. Elastic textiles have retained their extensible property. Thebest dry cleaning results were obtained with composite solvents 2 and 4.

With regards to the discoloration, we have observed a slight washing outin the case of the composite solvent without re-depositing of the latteron the other fabrics. In the case of the other composite solvents theresistance to discoloration is good and even better than that ofperchloroethylene when the dry cleaned fabrics are compared with thereference samples.

2) Behavior on the Linings:

The effect of composite solvents 1 to 6 as a dry cleaning solvent wasstudied on linings frequently encountered on textile articles such asbuttons, plastic or metal zippers and glued sequins.

The tests on the linings (buttons and accessories) have shown thatcomposite solvents 1 to 6 yield identical and even better results thanperchloroethylene with a preference for composite solvents 1, 2, 5 and 6which respect these elements more.

3) Behavior on Stains:

The fabrics studied contained dirt caused by the following contaminants:olive oil, chocolate (Nutella®), mayonnaise, lipstick, red wine, ink andwere compared with perchloroethylene and hydrocarbons. These tests werecarried out without the use of a intensifier (surfactant).

The results of these tests have shown that:

-   -   the composite solvents of examples 1 to 6 made it possible to        very easily clean the fatty stains without using additives.    -   the composite solvents of examples 1, 2, 4 and 6 are in        particular highly effective for the dry cleaning of stains due        to butter or olive oil, said stains are no longer visible after        the cleaning process.    -   the composite solvents of examples 1 and 2 have shown to be in        particular very effective for dry cleaning, in particular on        stains caused by chocolate, lipstick and wine, said stains        became less visible after the cleaning process contrary to        perchloroethylene which leaves larger stains.

The arrangement of the various elements and/or means and/or steps of theinvention, in the embodiments described hereinabove, must not beunderstood as requiring such an arrangement in all of theimplementations. In any case, it will be understood that variousmodifications can be made to these elements and/or means and/or steps,without leaving the frame of mind and scope of the invention.

1. A Unit for dry cleaning of textile articles using a composite solventcomprising several components comprising: a dry cleaning chamber (1)configured to mix, during a cleaning cycle, textile articles to becleaned with a composite solvent; a device (7) for recovering thecomposite solvent after the cleaning cycle; a treatment device (8) forremoving water and dirt and recycling at least a portion of thecomposite solvent for the purpose of using the recycled compositesolvent for another dry cleaning cycle, a re-adjustment device (9) forre-adjusting the recycled composite solvent by incorporating therein atleast a portion of the component or components that was lost in thetreatment device (8), wherein the device comprises at least: a buffertank (10) provided with at least one supply inlet (10 a) for therecycled composite solvent, with at least one inlet (10 b) for thesupply of at least the portion of the component or components of thecomposite solvent to be introduced into said buffer tank (10) in orderto re-adjust the composition of the recycled composite solvent, and withat least one outlet (10 c) for the recycled and re-adjusted compositesolvent, with this outlet (10 c) being connected to the storage tank (5)for the dry cleaning composite solvent, a storage tank (11) for one orseveral components of the dry cleaning composite solvent, and a meteringpump (14) of the quantity of the component or components of thecomposite solvent to be introduced into the buffer tank (10) throughsaid inlet (10 b) for the re-adjustment of the composition of therecycled composite solvent, this pump is connected upstream to at leastone storage tank (11) containing one or several components of the drycleaning composite solvent.
 2. The Unit according to claim 1, whereinthe re-adjustment device (9) is provided with an analyzer (15) whichmakes it possible to analyze the physical and/or chemicalcharacteristics of the recycled composite solvent, to determine thequantity of the component or components of the composite solvent to betaken from the storage tank (11) and to be introduced into the buffertank (10).
 3. The Unit according to claim 1, wherein the cleaningchamber (1) is provided with a perforated drum (2) intended to receivethe textile articles to be cleaned, said perforated drum (2) beingmounted rotatingly in said chamber, with the latter having: an opening(20) for the placing of textile articles to be dry cleaned in theperforated drum (2), with this opening able to be closed by a door or aporthole; an orifice (3) connected to a duct for introducing (4) thecomposite solvent which is placed in a storage tank (5); and an orifice(6) connected to the recovery device (7).
 4. The Unit according to claim1 wherein the device (8) for treating the used composite solventcomprises at least one filtration device (12) for filtering insolubledirt contained in said used composite solvent and a fractionateddistillation unit (13) comprises: an outlet for the removal of a topfraction F1 representing less than 15% w/w_(used composite solvent) andcontaining at least water, one or several azeotropes formed between thewater and one or several components of the composite solvent; and anoutlet for the recycling of an intermediate fraction F2 representingmore than 75% w/w_(used composite solvent) and containing the drycleaning composite solvent less at least one portion, by weight, of oneor of several of its components, said intermediate fraction F2 beingdirected after recycling to the buffer tank (10).
 5. The Unit accordingto claim 4, wherein the fractionated distillation unit (13) is providedwith a collection container (31) configured to receive in a first stepthe top fraction F1 before it is discharged to the removal tank (30),then in a second step, the intermediate fraction F2 before it is sent tothe buffer tank (10), said collection container (31) having adrawing-off point (31 a) in its lower portion, through which the topfraction F1 and the intermediate fraction F2 are removed to theirrespective tanks (30) and (10); and being provided with an analyzer (15a) making it possible to analyze the physical and/or chemicalcharacteristics of the top fraction F1 or of the fraction F2 in such away as to determine the quantity of the component or components of thecomposite solvent to be introduced into said buffer tank (10).
 6. TheUnit according to claim 5, wherein the removal tank (30) intended tocontain the top fraction F1, comprises a duct (300) connected to aninjection device (301) making it possible to inject, after N drycleaning cycles, said fraction F1 into the fractionated distillationunit (13) for the purpose of separating it into at least two fractions:one top fraction F′ 1 intended to be removed, and a fraction F2 intendedto be added, before the re-adjusting of the recycled composite solvent,to the intermediate fraction F2 collected after the cycle N of drycleaning.
 7. The unit according to claim 1, wherein the compositesolvent comprises at least: 40% to 80% w/w dipropylene glycol monomethylether, 5% to 40% w/w an amphiphilic solvent A having the followingformula: R—(O—C₃H₆)_(n)—OH (1) wherein n is an integer equal to 1 or 2,and R a C₃- or C₄-alkyl group, 10% to 40% w/w a dibasic ester B selectedfrom the group comprising dimethyl succinate, dimethyl glutarate,dimethyl adipate and mixtures thereof, and 0% to 10% w/w additionalcomponents.
 8. A method of dry cleaning of textile articles with acomposite solvent having a plurality of components and of recycling theused composite solvent for reuse, said method comprising: a) a drycleaning cycle comprising contacting fabric articles to be cleaned withthe composite solvent, b) recovering the used composite solventcontaminated with dirt and water at the end of the dry cleaning cycle,c) treating the used composite solvent in order to remove at least waterand dirt, and d) recycling at least a portion of the composite solventtreated in step c) for the purpose of using it for another dry cleaningcycle, wherein the composition of the recycled composite solvent isreadjusted by incorporating at least the portion, by weight, of thecomponent or the components of the composite solvent, which portion waslost during the treatment step aimed at removing the water and dirt. 9.The method according to claim 8, wherein the portion, by weight, to beincorporated in the composition of the recycled composite solvent isdetermined from the physical and/or chemical analysis of the recycledcomposite solvent.
 10. The method according to claim 8, wherein thetreatment step aimed at removing the water and dirt comprises afractional distillation.
 11. The method according to claim 10, whereinthe fractional distillation is conducted so as: to remove a top fractionF1 comprising less than 15% w/w used composite solvent and containing atleast water and one or several azeotropes formed between water and oneor more components of the composite solvent, and to collect anintermediate fraction F2 representing more than 75% w/w used compositesolvent containing the dry cleaning composite solvent less at least aportion, by weight, of one or more of its components, which portion waslost in the treatment comprising the fractional distillation.
 12. Themethod according to claim 11, wherein the top fraction F1 removed byfractional distillation in step c) is distilled at a temperature lessthan 82° C. and a pressure of 65 bars and comprises at least water,dipropylene glycol monomethyl ether, and optionally an amphiphilicsolvent A′ having the following formula: R′-0-C₃H₆—OH (I′) wherein R′represents a C₃- or C₄-alkyl group.
 13. The method according to claim11, wherein the intermediate fraction F2 recovered by fractionaldistillation in step c) distills at a temperature above 83° C. and undera pressure of 65 bars.
 14. The method according to claim 7, wherein theportion to be incorporated into the composition of the recycledcomposite solvent comprises at least dipropylene glycol monomethylether, and optionally an amphiphilic solvent A′ of formula R′—0-C₃H₆—OH(I′) wherein R′ represents an C₃- or C₄-alkyl group.
 15. The methodaccording to claim 13, wherein the top fraction F1 removed in step c) isrecovered in a drain tank, then, after N dry cleaning cycles, issubjected to a fractional distillation, which fractional distillation isconducted so as to remove a top fraction F1, said top fraction F1containing a major amount of water, and to recover a fraction F2, saidfraction F′2 being intended to be added, before step e) of readjustment,to the intermediate fraction F2 recovered after the N dry cleaningcycle.